Spatio-Temporal Low Count Processes with Application to Violent Crime Events

There is significant interest in being able to predict where crimes will happen, for example to aid in the efficient tasking of police and other protective measures. We aim to model both the temporal and spatial dependencies often exhibited by violent crimes in order to make such predictions. The temporal variation of crimes typically follows patterns familiar in time series analysis, but the spatial patterns are irregular and do not vary smoothly across the area. Instead we find that spatially disjoint regions exhibit correlated crime patterns. It is this indeterminate inter-region correlation structure along with the low-count, discrete nature of counts of serious crimes that motivates our proposed forecasting tool. In particular, we propose to model the crime counts in each region using an integer-valued first order autoregressive process. We take a Bayesian nonparametric approach to flexibly discover a clustering of these region-specific time series. We then describe how to account for covariates within this framework. Both approaches adjust for seasonality. We demonstrate our approach through an analysis of weekly reported violent crimes in Washington, D.C. between 2001-2008. Our forecasts outperform standard methods while additionally providing useful tools such as prediction intervals

Consultation on high frequency repeat victims in the Crime Survey - our response

The current methodology for handling repeat victimisation in the Crime Survey for England and Wales (CSEW) is capping. Repeat victimisations for any series of crimes are capped at maximum of 5 crimes before the data is used to produce crime rate estimates for England and Wales. The new proposals merely shift the level of this cap. Capping produces inaccurate estimates of crime which are systematically biased in specific ways, no matter what level the cap is set at. It is possible to increase the accuracy of crime estimates from the CSEW by deriving them from all reported crimes, and without increasing volatility by utilising three-year rolling averages. A move away from capping to deriving crime estimates based on all reported crimes would increase: relevance, accuracy, clarity, coherence and comparability of crime statistics and would better conform to ONS quality principles. A capping methodology does not conform to these ONS quality principles

A Time-Series Analysis of Crime and Drug Use in New York City

This report summarizes the results of a project which investigated the time series interrelationships between crime, drug use, police, and arrests in New York City. We use monthly data from 1970 through 1990 for New York City. We plot the individual time series for five different non-drug crimes, arrest rates for these crimes, drug deaths, number of police officers, and drug arrests in New York City. We find that drug usage, as proxied by drug deaths, increased from the mid-1980's to about 1988-1989. At the same time, felony drug arrests increased substantially. During the mid-1980's, there were increases in murders, assaults, and motor vehicle thefts. Robberies increased in the later 1980s and burglaries declined throughout the 1980s. Arrest rates and total arrests for non-drug crimes did not decline during this period of increased drug arrests. In a multivariate analysis, we found that the three property crimes investigated - robberies, burglaries and motor vehicle thefts - increased when there were unexpected increases in drug usage. We did not find such a relationship between drug use and murders or assaults, holding constant arrest rates and police. In addition, we found evidence of police deterrence, either directly, or through arrests, of property-related and assault offenses, but not for murders. Thus, in a time-series approach, we are able to find a causal relationship between drug usage and property-related felonies.

City business cycles and crime

We explore the influence of city-level business cycle fluctuations on crime in 20 large cities in the United States. Our monthly time series analysis considers seven crimes over an approximately 20-year period: murder, rape, assault, robbery, burglary, larceny, and motor vehicle theft. Short-run changes in economic conditions, as measured by changes in unemployment and wages, are found to have little effect on city crime across many cities, but property crimes were more likely to be influenced by changes in economic conditions than were more violent crimes. Contrary to the deterrence hypothesis, we find strong evidence that in many cities more arrests follow from an increase in crime rather than arrests leading to a decrease in crime. This is true especially for the more visible crimes of robbery and vehicle theft and suggests that city officials desire to remove these crimes from the public's view.Business cycles ; Cities and towns ; Crime

Crimes Against Children by Babysitters.

Presents information on the frequency and nature of crimes committed against children by babysitters. As part of OJJDP\u27s Crimes Against Children Series, the Bulletin draws on the FBI\u27s National Incident-Based Reporting System (NIBRS) to examine victim and offender characteristics, including gender, age, type of injury, and victim-offender relationship. The Bulletin also presents an overview of how NIBRS works to collect a wide range of criminal information for a variety of offenses. The Bulletin concludes by examining the implications of NIBRS data, particularly in regard to the severity of threat posed to children by babysitters

No Child Left Behind: The Adam Walsh Act and Pennsylvania Juvenile Sex Offenders

At a White House ceremony on July 27, 2006, President Bush signed into law the Adam Walsh Child Protection and Safety Act of 2006. At the ceremony, the President hailed the Walsh Act as being comprehensive and an important part of the “solemn responsibility” of lawmakers to protect children. Indeed, the Walsh Act is the latest in a series of federal legislation, dating back to the 1980s, which aims to protect the public, and children in particular, from becoming victims of sexual crimes. The public’s fear of the rapist and the child molester led to a great increase in the criminal penalties for sexual crimes throughout the 1980s and 1990s, as well as the imposition of federal laws focusing on these crimes. And at a time when television shows such as “To Catch a Predator” receive millions of viewers, it is clear that the nation’s fear of those who would commit sexual crimes against children, and the desire that they be brought to justice, remains at a fever pitch. By passing the Walsh Act, Congress and the President responded to a national outcry that children were not safe from sex offenders

A Statistical Approach to Crime Linkage

The object of this paper is to develop a statistical approach to criminal linkage analysis that discovers and groups crime events that share a common offender and prioritizes suspects for further investigation. Bayes factors are used to describe the strength of evidence that two crimes are linked. Using concepts from agglomerative hierarchical clustering, the Bayes factors for crime pairs are combined to provide similarity measures for comparing two crime series. This facilitates crime series clustering, crime series identification, and suspect prioritization. The ability of our models to make correct linkages and predictions is demonstrated under a variety of real-world scenarios with a large number of solved and unsolved breaking and entering crimes. For example, a na\"ive Bayes model for pairwise case linkage can identify 82\% of actual linkages with a 5\% false positive rate. For crime series identification, 77\%-89\% of the additional crimes in a crime series can be identified from a ranked list of 50 incidents

COVID-19: Examining the Impact of the Global Pandemic on Violent Crime Rates in the Central Valley of California

This study focuses on how a global pandemic like COVID-19 affects violent crimes in the city of Stockton, California. The violent crimes that we will be examining are homicide, robbery, rape, simple assault, and aggravated assault. We obtained crime data from the LexisNexis Community Crime Map and obtained COVID-19 data from the San Joaquin County Health Department regarding the city of Stockton. We developed the results of this research by using time-series plots and interrupted time-series analysis. Our results demonstrate that COVID-19 caused a statistically significant change in the slope for rape, robbery, and simple assault violent crimes. Finally, we discuss in our policy implications section that the Stockton Police Department should establish more community outreach programs that could help prevent these types of violent crimes

Prostitution of Juveniles: Patterns From NIBRS.

Examines the prostitution of juveniles by analyzing incidents of this problem that come to the attention of law enforcement. Part of the Crimes Against Children Bulletin Series, this Bulletin draws on data from the FBI’s National Incident-Based Reporting System (NIBRS) to provide a profile of juvenile prostitution, noting characteristics that distinguish it from its adult counterpart. Although information about the prostitution of juveniles is scarce, the data from NIBRS can be used to help juvenile justice officials and others better identify and respond to the sexual exploitation of youth